Color diffusion transfer dye image-forming material binder layers containing a water-soluble cellulose salt

ABSTRACT

Photographic products for forming diffusion transfer images, particularly multicolor transfer images, which products contain one or more gelatin-containing layers including the addition of a water-soluble cellulose salt.

Kiiem et a1.

[451 *Sept. 9, 1975 COLOR DIFFUSION TRANSFER DYE [56] References CitedIMAGE-FORMING MATERIAL BINDER UNITED STATES PATEN LAYERS CONTAINING A 23 590 M1944 J ff t I TS 96 13 a e e a WATER-SOLUBLE CELLULOSE SALT2,956,883 10/1960 De Pauw et al. 96/1 13 Inventors: Peter O. Kliem,Weston; Jerome L. 3,077,400 2/1963 Rogers 96/29 D Reid Wayland of MassKliem Ct alt Assignee:

Notice:

Filed:

Appl. No.: 423,669

US. Cl.

96/74; 96/77; 96/113 Int. Cl?" G03C 7/00; G03C 5/54; 603C 1/76; G0303/00 Field of Search 96/3, 29 D, 77, 99, 100,

Polaroid Corporation, Cambridge, Mass.

Primary Examiner-Norman G. Torchin Assistant ExaminerRichard L.Schilling The portion of the term of this patent subsequent to Dec. 12,1989, has been disclaimed.

Dec. 11,1973

[57 ABSTRACT Attorney, Agent, or Firm-Gerald L. Smith Photographicproducts for forming diffusion transfer images, particularly multicolortransfer images, which products contain one or more gelatin-containinglayers including the addition of a water-soluble cellulose salt.

LAYER DYE DEVELOPER LAYER SENSITIVE SILVER HALIDE EMULSION LAYER DYEDEVELOPER LAYER SILVER HALIDE EMULSION LAYER DYE DEVELOPER LAYERSENSITIVE SILVER HALIDE EMULSION LAYER LAY E R LAYER LAYER 4 Claims, 6Drawing Figures PATENTED 9*975 3,904,417

sum 1 BF 3 COLOR DIFFUSION TRANSFER DYE IMAGE-FORMING MATERIAL BINDERLAYERS CONTAINING A WATER-SOLUBLE CELLUIJOSE SALT BACKGROUND The presentinvention is directed to providing new and improved diffusiontransfer-process photographic film units adapted to provide, as afunction of the pointto-point degree of photoexposure, by diffusiontransfer processing, a dye transferimage.

A number of photographic systems for forming images by diffusiontransfer are well known in the art. Generally speaking, such systemscomprise the steps of photoexposi'ng a light-sensitive material,typically a light-sensitive silver halide layer, to form a developableimage; contacting the thus exposed light-sensitive material with aphotographic processing composition to develop said image and to form animagewise distribution of mobile and diffusible image-formingconstituents; and transferring this imagewise distribution, at least inpart, by diffusion, to an image-receiving layer to impart thereto thedesired transferimage. The image-receiving layer may be contained on aseparate support, i.c., as a separate element, or in lieu thereof, theimage-receiving layer and the photosensitive layer may be contained as aunitary product on the same support, e.g., as a laminar produceincluding the photosensitive layer, the image-receiving layer, and anyother additional layers which maybe desirable or necessary in theparticular photographicsystem employed.

Black-and-white transfer images may beprovided by the well known silvertransfer system wherein a lightsensitive silver halide layer, e.g., agelatino silver halide emulsion layer, is exposed and then developedwith an aqueous alkaline processing composition including a silverhalide developing agent and a silver halide solvent to form in terms ofunexposed areas an imagewise distribution of a soluble silver complexwhich is then transferred, at least in part, by diffusion, to asilverreceptive stratum where it is reducedto impart thereto a positivesilver transfer image. I

Color transfer images may be obtained by various systems employingcolor, image-providing materials which may be complete dyes or dyeintermediates, e.g,, color couplers The color image-providing materialmay be initially insoluble or nondiffusible in the particular processingcomposition employed or it may be initially soluble or diffusible in theprocessing composition. In either instance, and in accordance with theparticular image-forming mechanism employed, upon contacting the exposedphotosensitive layer with the appropriate processing composition, animagewise distribution of soluble and diffusible color image-providingmaterial is, formed and this imagewise distribution is then transferred,at least in part, by diffusion, to a superposed image-receiving layer,e.g., a dyeable stratum, to impart thereto a color transfer image. Thisimage may be monochromatic or multicolor, depending upon the systememployed, particularly whether two or more photosensitive layers andassociated color image-providing material are so employed.

A particularly useful system for preparing color transfer images is thatdescribed and claimed in U.S. Pat. No. 2,983,606 employing as the colorimageproviding material a dye developer, i.e., a dye whiich is also asilver halide developing agent. In such a system, an exposed silverhalide layer containing a developable image is developed by contactingit with an aqueous alkaline solution containing a dye developer. The dyedeveloper develops the exposed silver halide and is in turn oxidized toprovide an oxidation product which is less mobile anad diffusible thanunreacted (unoxidized) dyedeveloper. An imagewise distribution of theu'noxidized dye developer is then transferred, by diffusion, to adyeable stratum to impart thereto a positive color transfer image.

Other color image-providing materials and systems employing them to formcolor transfer images, are also known in the art. By way ofillustration, mention may be made of the materials and systems disclosedin the.

following U.S. Pat. Nos: 2,647,049; 2,661,293;

3,364,022; 3,443,939; 3,443,940; 3,443,941; etc.

In any of the aforementioned systems monochromatic color transfer imagesmay be obtained by employing a photographic product or film unitcontaining a single photosensitive layer which is exposed and thendeveloped in the presence of one or, if desired, a mixture of colorimage-providing materials. Multicolor images may be obtained in themanner known in the art by employing aphotographic product containingtwo or more selectively sensitized photosensitive layers each havingassociated therewith a color imageproviding material of predeterminedspectral absorption characteristics. A typical photographic product forpreparing multicolor images comprises a photosensitive elementcomprising a blue-, a greenand a redsensitive silver halide emulsionlayer having associated therewith in the same or in a contiguous layer ayellow, a magenta and a cyan color image-providing material,respectively. Thus, a typical photographic product employing dyedevelopers may comprise a support carrying, in order, a cyan dyedeveloper layer,-a red-sensitive silver halide emulsion layer, a magentadye developer layer, a green-sensitive silver halide emulsion layer, ayellow dye developer layer, and a blue-sensitive silver halide emulsionlayer. Photographicproducts contemplated for use in forming multicolortransfer images may, and preferably do contain interlayers disposedbetween the red-sensitive silver halide emulsion layer and the magentadye developer [or other color imageproviding material] layer and/orbetween the greensensitive silver halide emulsion layer and the yellowdye developer. An additional or auxiliary layer may be, and

' preferably is, disposed over the blue-sensitive silver halide emulsionlayer.

Common to all of these systems is a photographic product or film unithaving one or more gel-containing layers. The gel-containing layer maybe the lightsensitive layer or layers, e.g., a gelatino silver halideemulsion layer, the layer containing the color imageproviding material,e. g., any of the dye developer layers previously described and/or theinterlayers, auxiliary layer, etc. The dye developers employed may beincorporatad with their associated silver halide emulsion layer or, inthe preferred embodiment, in a separate layer behind the respetivesilver halide stratum. The developer is distributed in a film-formingnatural, or synthetic, polymer, for example, gelatin, polyvinyl alcohol,and the like, adapted to be permeated by a chosen diffusion transferfluid processing composition. To provide a more efficient and usefulfilm unit product incorporating the above-outlined features, it isdesirable to utilize low-gel" systems. Such systems provide forsignificant reduction in the gelatin constituent of any layer or strata.The com '"cni lower strata thicknesses serve to improve diffusiontransfer activity. Selective additives,.for instance, those described inUS. Pat. No. 3,705,798 have been found useful in deriving low gelsystems. However, in some gelatin carried dyedeveloper strata, certaintypical additives may tend to promote aggregating effects and the like.

SUMMARY OF THE INVENTION The present invention is directed to new andimproved negative/positive integral or multicomponent diffusion transferprocess photographic film units adapted to provide, by diffusiontransfer processing, a photographic color image reproduction as afunction of the exposure of such film units to incident actinicradiation.

In one aspect, the photographic film unit of the invention provides forthe improved performance of diffusion transfer process dye image-formingmaterials. This is achieved by providing with the dye dispersion, withinan aqueous alkaline solution polymeric binder, a water-soluble cellulosesalt. Preferably, this salt is selected as sodium cellulose sulfate.

In another aspect, the watersoluble cellulose salt may be incorporatedwith silver halide emulsion layers having associated therewith dyeimageproviding materials, or in each of discrete strata thereof.

The film unit assemblys construction employed in the practice of thepresent invention may comprise a film unit of the general type set forthin US. Pat Nos. 3,4l5,644,- and -6; 3,473,925; 3,573,042,-3 and -4;

3,576,625 and 6; 3,594,164 and -5; 3,615,42l;

3,620,724; 3,647,434,-5 and -7; 3,661,585; 3,672,890; and 3,689,262, andwill include, disposed in a photosensitive element which contains aplurality of layers including, in predetermined order, two dimensionallystable layers at least one of which is transparent and intermediate saiddimensionally stable layers, a plurality of layers including at least adyeable polymeric layer and a photosensitive layer comprising aplurality of strata containing one or more photosensitive silver halidelayers, each having associated therewith a diffusion transfer processdye image-forming material disposed within a polymeric binder andincorporating a water soluble celluslose salt. The unit also may containmeans for providing a'processing composition in contact with thephotosensitive layers at a select location within the unit in dependenceupon its particular structure.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view,partially in section, showing atypical photographic film unit embodyingthe invention;

FIG. 2 is an exploded perspective view of the film unit of FIG. 1;

vFIG. 3 is a somewhat schematic, longitudinal, sectional view of oneembodiment of the film unit, the thickness of the materials beingexaggerated for purposes of clarity of illustration;

FIG. 4 is a diagrammatic, enlarged, cross-sectional view of a portion ofone embodiment of a film unit illustrating in detail the arrangement oflayers of materials therewithin;

4 FIG. 5 is another schematic, longitudinal sectional view of anotherembodiment of the film unit, the thickness of materials and componentsbeing exaggerated for purposes of clarity of illustration; and

FIG. 6 is a diagrammatic, enlarged, cross-sectional view of a portion ofthe film unit of Flg. 5.

DETAILED DESCRIPTION Reference is now made to FIGS l and 2 of thedrawings wherein there is illustrated one film unit structure of a typewhich may embody the invention. The film unit, designated 10, generallyincludes dimensionally stable layers or sheets 12 and 14, and arupturable container 16 holding a quantity of processing liquid 17. Thetwo sheets and processing liquid include all of the materials andreagents required to produce a full-color photographic print asdescribed by appropriate ones of the aforementioned patents.

The basic construction of the film unit 10 remains somewhat the same forunitary image producing systems which may be incorporated therewithin.For such structures, distinctions may be found in the nature of supportsheets 12 and 14, that is, whether one or both are transparent, and thenoted disposition of various layers and strata coated thereupon. As setforth in the earlier referenced patents, the structure of the film unitsmay be designed for more or less typical operation whereinphotosensitive and image receiving portions are joined for processingand separated thereafter following an interval of imbibition. In theparticular embodiment shown in FIGS. 1 and 2, the photosensitivestructure of the unit is exposed and the image is viewed through sheet14 which, accordingly, is transparent.

In addition to sheets 12 and 14 and container 16, film unit 10 includesa mask or binding element 18 and-a trapping element 20. Sheets 12 and 14are secured in face-to-faee relation at their lateral and trailingmargins by binding element 18 as shown. Element 18 preferably is formedof a light opaque material.

Container 16 is of a type shown in US. Pat. No. 2,543,181 and is formedby folding a rectangular blank of a fluid-impervious sheet materialmedially and sealing the marginal sections of the blank to one anotherto form a cavity for containing processing liquid 17. The seal along themarginal section of the container adjacent sheets 12 and 14 is weakerthan the end seals. Accordingly, upon the application of a predeterminedcompressive force to the walls of the container, there will be generatedwithin the liquid a hydraulic pressure sufficient to separate the notedweaker seal so as to provide for the discharge of fluid 17 at a selectlocation intermediate sheets 12 and I4. Container 16 is retained inplace by appropriate portions of binder element 18. In processing thefilm units shown, the unit is advanced, container 16 foremost, relativeto and between a pair of pressure-applying members such as rolls (seeFIG. 3). These members initially apply compressive pressure to thecontainer to cause it to eject its liquid contents between sheets 12 and14, then distribute the mass of Looking to FIGS. 3 and 4, an embodimentfor film unit 10 in which dimensionally stable sheet 14 is transparentand sheet 12 is opaque, is revealed in exaggerated detail. As shown moreclearly in FIG. 4, the laminate structure incorporates photosensitivelayers hav ing a plurality of strata. For instance, the photosensitivestrata includes, in order, cyan dye developer layer 24; red sensitivesilver halide emulsion layer 26; an interlayer 28; magenta dye developerlayer 30; greensensitive silver halide emulsion layer 32; interlayer 34;yellow dye developer layer 36; blue-sensitive silver halide emulsionlayer 38; auxiliary layer 40 which may contain an auxiliary silverhalide developing agent; image-receiving layer 42 which may be a dyeablepolymeric layer; spacer layer 44 and neutralizing layer 46. The latterlayer isjuxtaposed to transparent dimensionally stable sheet layer 14.

Supporting sheets or elements 12 and 14 may be formed from a variety ofmaterials, for instance, paper base materials, ethylene glycolterephthalic acid; vinyl chloride polymers; polyvinyl acetate;polyamides; polymethacrylic acid; methyl and ethyl esters; cellulosederivatives, such cellulose acetate, triacetate, nitrate, propionate,butyrate acetate or acetate butyrates; cross linked polyvinyl alcohol,and so forth.

The respective silver halide emulsion layers may comprise gelatino mixedsilver halide emulsions, e.g,, silver iodobromide emulsions, selectivelysensitized as noted above.

The interlayers and/or the auxiliary layer may com prise gelatin or someother suitable material. For example, each of the two inter-layers maycomprise the coalescence of a synthetic polymeric latex and acomposition which provides selective permeability thereto in accordancewith the invention described in a now abandoned application for US.Patent by Avtcges et al., Scr. No. 880,205, filed Nov. 26, 1969,

The dye developers are compounds which contain, in the same molecule,both the chromophoric system of a dye and also a silver halidedeveloping function. By a silver halide developing function is meant agrouping adapted to develop exposed silver halide. A preferred silverhalide development function is a hydroquinonyl group. Other suitabledeveloping functions include ortho-dihydroxyphenyl and orthoandpara-amino substituted hydroxyphenyl groups. In general, the developmentfunction includes a benzenoid developing function, that is, an aromaticdeveloping group which forms quinonoid quinone substances when oxidized.

The dye developers are preferably selected for their ability to providecolors that are useful in carrying out subtractive color photography,that is, the previously mentioned cyan, magenta and yellow. The dyedevelopers employed may be incorporated in the respective silver halideemulsions or, in the illustrated embodiment. in a separate layeradjacent the respective silver halide stratum. The dye developers aredistributed in a film-forming natural or synthetic polymer, for example,gelatin, polyvinyl alcohol, and the like, adapted to be permeated by thechosen diffusion transfer fluid processing composition.

The photosensitive layer or component of unit 10 for the instant orrelated structural embodiment would include layers 12, 24-40 and may beprepared, for exam plc, by coating, in succession on a gelatin subbedopaque cellulose triacetatcfilm base, the following layers:

l. a layer of the cyan dye developer l,4-bis-( ,8-

[hydroquinonyl-a-methyll-ethylamino)5,8- dihydroxy-anthraquinonedispersed in gelatin and coated at a coverage of about 150 mgs./ft. ofdye and about 200 mgs./ft.? of gelatin;

2. a red-sensitive gelatino-silver iodobromide emul-, sion coated at acoverage of about 200 mgs./ft. of silver and about lOO mgs/ft. ofgelatin;

3. a layer of gelatin coated at a coverage of about 200 mgs./ft. i

4. a layer of the magenta dye developer Z-(p-[B- hydroquinonylethyll-phenylazo )-4-isopropoxyl naphthol dispersed in gelatin and coated ata coverage of mgs./ft. of dye and about .100 mgs./ft. of gelatin; 1

5. a green-sensitive gelatino-silver iodobromide emulsion coated at acoverage of about mgs./ft. of silver and 60 mgs./ft.'- of gelatin;

6. a layer of gelatin coated at a coverage of about 150 mgs./ft.

7. a layer of the yellow dye developer 4-(p-[B- hydroquinonylethylI-phenylazo )-3-( N-nhexylcarboxamido )-l-phenyl-5-pyrazolone dispersedin gelatin and coated at a coverage of about 40 mgs./ft. of dye and 50mgs./ft. of gelatin;

8. a blue-sensitive gelatino-silver iodobromidc emulsion coated at acoverage of about 60 mgs./ft. of silver and about 50 mgs./ft. ofgelatin; and v 9. a layer containing 4'methylphenyl hydroquinonedispersed in gelatin and coated at a coverage of about 10 mgslftf of4-methylphenyl hydroquinone and about 30 mgs./ft. of gelatin.

Where the structural embodiment of the photographic unit is one whereinthe photosensitive and image receiving portions thereof are separatedfollowing an interval of imbibition, the image receiving portion may beone as described, for example, in U.S. Pat. No. 3,362,819.

In the embodiment of FIGS. 3 and 4, disclosed, for example, in theearlier referenced patents, including No. 3,415,644, a unitary orcomposite arrangement is provided wherein the processing composition 17provided from container 16 is unidirectionally discharged intermediateauxiliary layer 40 and imagereceiving layer 42. A somewhat schematicrepresentation for this geometry is revealed in FIG. 3, the figure alsoshowing the forwardmost portion of container 16 being introduced betweenpressure applying rolls 50 and 52.

The unitary or composite film unit of the type shown in FIGS. 3 and 4,may be prepared by first successively coating layers 24-40 on support 12in the'manner described immediately above. Then transparentdimensionally stable sheet 14., for instance cellulose triacetate filmbase, may be coated, in succession, with-the fol lowing illustrativelayers:

1. the partial butyl ester of polyethylene/maleic anhydride eopolymerprepared by refluxing, for 14 hours, 300 grams of high viscosity poly-(ethylene/maleic anhydride), grams of n-butyl alcohol and 1 cc. of 857cphosphoric acid to provide a polymeric acid layer approximately 0.75mils. thick; I

,2. a solution of hydroxypropyl cellulose in water to provide apolymeric spacer layer approximately 0.075 mils. thick;

3. a 2:1 mixture, by weight, of polyvinyl alcohol andpoly-4-vinylpyridine, at a coverage of approximately 600 mgs./ft.'-. toprovide a polymeric imagereceiving layer approximately 0.40 mils. thick;and

4. then baking the element at 180F. for 30 minutes and cooling.

The two components thus prepared may then be taped together in laminateform, for instance, by binder element 18 at their respective edges.Rupturable container 16 containing an aqueous alkaline processingsolution 17 comprising:

Water 100 cc. Potassium hydroxide l l.2 grams Hydroxycthyl cellulose(high 3.4 grants viscosity) I commercially available from HerculesPowder Co., Wilmington. Delaware, under the trade name Natrasol 250N-henzyl-a-picolinium bromide grams Bcnxotriazole grams Titanium dioxide40.0 grams may then be mounted on the leading edge of each of thelaminates by pressure sensitive binding element 18 or other suitablemeans providing the above-noted necessary geometry for properdistribution of the fluid intermediate layers 40 and 42. Subsequent tothe distribution of the processing solution, a multic lor dye transferimage formation at layer 42 may be viewed through transparent sheet 14against a reflecting background, for instance, provided by the titaniumdioxide constituent of the solution.

Turning to FIGS. and 6, another film unit structure appropriate for theinstant invention is illustrated. Described in detail in US. Pat. No.3,594,164, film unit 60 assumes the general configuration of unit shownin FIGS. 1 and'2, however, its laminar structure as well as the geometryof its dimensionally stable layers and processing fluid container aredifferent. Film unit 60 comprises a rupturable container 62 retaining,prior to processing, aqueous alkaline solution 64, photosensitivelaminate 66 including, in order, blue-sensitive silver halide emulsionlayer 68 containing yellow dye dcveloper appropriately dispersed withina gelatin carrier; interlayer 70; green-sensitive silver halide emulsionlayer 74 containing magenta dye developer; interlayer 74; red-sensitivesilver halide emulsion layer 76 containing cyan dye developer; opaquelayer 78; imagereceiving layer 80; spacer layer 82; neutralizing layer84; dimensionally stable transparent layer 86 and dimensionally stableopaque sheet 88 (FIG. 5). Both layer 86 and sheet 88 preferably compriseprocessing composition impermeable flexible sheet material.

The composite may be provided with a binding member extending around,for example, the specified edges of the laminate, as illustrated in thefigures. The binding member may comprise a pressure-sensitive tape,portions of which are revealed at 90 securing laminate elements togetherat the composite specified edges. Tape 90 will also act to maintainprocessing composition 64 intermediate sheet 88 and photosensitivelaminate 66 upon application of compressive pressure to container 62 anddistribution of its contents intermediate the stated elements. Undersuch circumstances, binder element or tape 90 will act to prevent edgeand end leakage of processing composition from the film unit during andsubsequent to photographic processing.

Rupturable container 66 may be configured in similar fashion and willoperate according to the general principals of the container describedat 16 in connection with FIGS. 1-4.

Container 62 is fixedly positioned and extends transverse to a leadingedge of photosensitive laminate 66 whereby to effect unidirectionaldischarge of the containers contents 64 intermediate sheet 88 andsurface 92 of blue-sensitive silver halide emulsion layer 68, uponapplication of compressive force to container 62. Thus, container 62, asillustrated in FIG. 5, is fixedly positioned and extends transverse to aleading edge of laminate 66 with its longitudinal marginal seal 94directed toward the leading edge of surface 68. Container 62 is fixedlysecured to laminate 66 by extension 96 of binder or tape in combinationwith a separate retaining member such as tape 98 extending over aportion of the opposite wall of the container and a portion of laminate66's surface.

Sheet 88 is fixedly coupled to tape 98 extending transverse the leadingedge of film unit 60 and is adapted to be superposed, subsequent tophotoexposure of laminate 66, on and coextensive with surface 92 ofblue-sensitive emulsion layer 68, at least during processing, tofacilitate distribution of processing composition 64 upon compressiverupture of container 62 and unidirectional discharge of its contentsintermediate surface 92 and superposed sheet 88.

Extension flap 30 of binder tape 90 may be of such area and dimensionthat upon, for example, manual separation of container 62 subsequent todistribution of the composition, from the remainder of the film unit 60,flap 96 may be folded over the edge of laminate 66 to facilitatemaintenance of the composite structural integrity. Preferably, however,the film unit will be maintained intact subsequent to processingincluding retention of the exhausted container, the processingcomposition and sheet element in the spatial position assumed duringprocessing. In such instance, the processing composition employed shouldpossess the requisite adhesive capacity, in both fluid and dry states,to enhance the integrity and stability of the spatial arrangementassumed.

In general, in a particularly preferred embodiment, the processingcomposition 64 and/or sheet 88 when distributed will be sufficientlyopaque to prevent further exposure of the film units silver halideemulsion or emulsions, by actinic radiation incident on sheet 88, duringprocessing of the unitin the presence of radiation actinic to theemulsion or emulsions. Accordingly, the film unit detail may beprocessed, subsequent to exposure, in the presence of such radiation, inview of the fact that the silver halide emulsiop or emulsions of thelaminate may be appropriately protected from incident radiation, at onemajor surface by the opaque layer and layers 78 and at the remainingmajor surface by an opaque processing composition 64 and/or opaque sheet88 as further described hereinafter. Note that, as before, processing iscarried out by drawing the assembly 60 through processing rolls as at100 and 102. As in the earlier embodiments, the binder tapes as at 90also are opaque to prevent edge leakage of actinic radiation. Theselected opaque layer or layers 78, however, should be one providing abackground suitable for viewing the dye developer transfer image formedin the dyeable polymeric layer. In general, while substantially anypermeable opaque layer may be employed, it is preferred that it beselected so as not to interfere with the color integrity of the dyetransfer image, as viewed by the observer, and, most preferably, alayerwhich is aesthetically pleasing to the viewer and does not providea background noise signal degrading, or detracting from, the informationcontent of the image.

The opaque layer may comprise substantially any opacifying agentcompatible with the photographic system, such asffor example, bariumsulfate, zinc oxide, titanium dioxide, barium stearate, silver flake,silicates, illumina, zirconium oxide, zirconium acetyl acetate, sodiumzirconium sulfate, kaolin, mica, and the like, which may be distributedin a permeable polymeric matrix binder, such as, for example,gelatin,'polyvinyl alcohol and the like. The opacifying capacity of theopaque layer may be improved beyond that ordinarily obtained by theaddition of an additional agent such as carbon black.

The opacifying agent dispersed in processing composition 64 may be anyof the multiplicity of such agents known in the art such as carbonblack, iron oxide, titanium (lll) oxide, titanium (111) hydroxide, andthe like.

Film unit 60 is exposed to radiation actinic to photosensitive laminate66 incident on the surface thereof. To provide for such exposure, sheet88 is retained in a position away from covering relationship withsurface 68. Following exposure, the unit 60 is drawn through rolls 100and 102 to effect superpositioning of sheet 88 contiguous to surface 92of laminate 66 and to apply suitable compressive pressure to container62 with resultant distribution of processing composition 64.

Processing composition 64 permeates emulsion layers 68, 72 and 76 toinitiate development of the latent images contained in the respectiveemulsions. The cyan, magenta and yellow dye developers of these layersare immobilized, as a function of the development of their respectiveassociated silver halide emulsions,

preferably substantially as a result of their conversion from theirreduced form to their relatively insoluble and non-diffusible oxidizedform, thereby providing image-wise distributions of mobile, soluble anddiffusible cyan, magenta and yellow dye developer, as a function of thepoint-to-point degree of their associated emulsions exposure. At leastpart of the image-wise distributions of mobile cyan, magenta and yellowdye developer transfer, by diffusion, to processing compositionpermeable polymeric layer 82, permeable spacer layer 84 and to polymericacid layer 86 whereby solution 64 decreases in pH, as a function ofneutralization, to a pH at which the cyan, magenta and yellow dyedevelopers, in the reduced form, are substantially non-diffusible, toprovide thereby a stable multicolor dye transfer image viewable throughdimensionally stable transparent layer 86.

It may be observed that in the structure of the film unit of FIGS. 5 and6, the silver halide emulsion and the associated dye developer areformed within a singular binder. It should be appreciated thatthestructure may be formed wherein the dye developer layers are providedwithin a separate layer and binder. 7

Film units similar to. that set forth the drawings may be prepared, forexample, by coating in succession, on a transparent cellulose triacetatefilm basef l. the partial butyl ester of polyethylen e/maleic anhy- 6dride eopolymer prepared by refluxing for 14 hours, about 300 grams ofhigh viscosity poly- (ethylene/maleic anhydride), about 140 grams ofn-butyl alcohol and about 1 cc. of phosphoric acid to provide apolymeric acid layer approximately 0.75 mil. thick;

2. a solution of hydroxy propyl cellulose in water to provide apolymeric spacer layer approximately 0.075 mils. thick;

3. a 2:1 mixture, by weight, of polyvinyl alcohol andpoly-4-vinylpyridine, at a coverage of approximately 600 mgs./ft. toprovide a polymeric imagereceiving layer approximately 0.40 mils. thick;

4. a layer of titanium dioxide dispersed in hydroxyethyl cellulose andcoated at a coverage of about 1,200 mgs./ft. of titanium dioxide andabout 30 mgslft. of hydroxyethyl celulose;

5. a layer of gelatin coated at a coverage of about 200 mgs./ft.

6. a layer of the acrylic latex sold by Rohm and Haas Co., Philadelphia,Pa., under the trade designation Rhoplex AC-6l coated at a coverage ofabout 1 l0 mgs./ft.

7. a layer of carbon black dispersed in hydroxyethyl cellulose coated ata coverage of about 150 mgs./ft. carbon black and about 3.0 mgsJft.hydroxyethyl cellulose; I

8. a layer of the cyan dye developer 1,4-bis-(Blhydroquinonyl-a-methyl]-ethyl-amino)-5,8- dihydroxy-anthraquinone andcarbon black dispersed in gelatin and coated at a coverage of about '50mgs./ft. of dye, about 180 mgs./ft.- of carbon black and about 63mgs./ft. of gelatin;

9. a red-sensitive gelatino silver iodobromide emulsion coated at acoverage of about mgs./ft. of silver and about 22 mgs./ft. of gelatin;

10. a layer of Rhoplex AC-6l coated at a coverage of about'8O mgs./ft. I

1 1. a layer of the magenta dye developer 4- isopropoxy-2-[p-(B-hydroquinonyl ethyl phenylazol-naphthalene-l-ethoxy acetate dispersedin a green-sensitive gelatino silver iodobromide emulsion coated at acoverage of about 80 mgs/ft. of dye, about 110 mgs./ft. of silver andabout 150 rngs./ft. of gelatin;

12. a layer of the last-mentioned magenta dye developer dispersed ingelatin at a coverage of about 20 mgs./ft. of dye and about 30 mgs./ft.gelatin;

13. a layer of Rhoplex AC-6l coated at a coverage of about 1 10 mgs./ft.

14. a layer of the yellow dye developer 4-( p-[B- hydroquinonyl ethyl]-phenylazo )-3-( N-nhe xyl carboxamido 1 -phenyl-5-pyrazolone dispersedin gelatin and coated at a coverage of about mgs./ft. of dye and about175 mgs./ft. of gelatin;

15 a blue-sensitive gelatino silver iodobromide emulsion coated at acoverage of about mgs./ft. of silver and about 28 mgs./ft. of gelatin;and

16. a layer containing 4-methylph enyl hydroquinone dispersed in gelatinat a coverage of about 20 mgs:/ft. of 4-methylphenyl hydroquinone andabout '30 mgs./ft. of gelatin.

A rupturable container comprising an outer layer of paper, intermediatelayer of lead foil and an inner liner or layer of polyvinyl chlorideretaining an aqueous alkaline processing solution comprising:

cc. gms. gms.

gms. gm.

6.4 gms.

and an opaque cellulose triacetate sheet may then be fixedly mounted onthe leading edge, of each of the laminates, by pressuresensitive tapesinterconnecting the respective sheets, containers and laminates, suchthat upon application of compressive pressure to the container andsuperpositioning of the sheet, the containers contents will bedistributed, upon rupture of the containers marginal seal, intermediatethe cellulose triacetate sheet and the 4-mcthylphenyl hydroquinonecontaining layer.

In accordance with the instant invention, film unit structures of thegeneral designs described above advantageously may be fabricatedincorporating low gel systems. As is described .in US. Pat. No.3,705,798 by the present inventors, such systems may be derived byincorporating select additions of watersoluble anionic polymericmaterials, for instance, within the silver halide layers. Preferredmaterials for this purpose are the salts of polyvinyl hydrogen phthalate(PVHP). When added within appropriate gelatin supported layers, theadditives permit the derivation of greater dye transfer densities andfaster diffusion rates than can be obtained with like layers containinggelatin alone. The improved dye transfer performance, at least inpart,derives from the fact that the combination permits one to use layerscontaining less matrix or carrier while still providing the desiredphysical properties such as viscosity that one could provide employingthe gelatin alone. The employment of lesser amounts of carrier, forexample, for the silver halide and color image-providing material,permits the deposition of thinner layers of same. This in turn evolves asystem presenting less of a barrier to dye transfer. Additionally,improved image resolution is realized inasmuch as the available extentof laterally directed diffusion is more restricted. The addition of awater-soluble salt of PVHP to a gelatino silver halide solution afterripening also provides a decrease in fog level which in turn furthercontributes to dye transfer control and subsequent color quality of thetransfer image.

It now has been determined that the addition of a water-solublecellulose salt, preferably sodium cellulose sulfate (SCS), to thegelatin layers not only permits the fabrication of a low gel system, butalso has no deleterious effects within the dye containing layers. Forinstance, in certain applications, gel/dye aggregates might otherwise beformed during post-production storage periods. The effectiveness ofincorporating a water-soluble cellulose salt as the thickening agentpermitting derivation of a low gel system within dye layers may beevidenced in the following examples.

The use of sodium cellulose sulfate as a gel reduction additive to amagenta dye transfer developer-gelatin layer permitted a change in thegel/dye (weight-toweight) ratio from a value of 0.875 using a moretypical additive such as a condensed napthylene sulfonate to 0.600 whereSCS' is utilized. This represents a 31.4% reduction in the gelatinconstituent. The formulation deriving this 0.600 gel-to-dye ratio was asfollows:

7.20% l:l chrome complexed azo dye developer 0.21% Lomar D" a condensednapthylene sulfonate used here as a dispersing agent. (Commericallyavailable from Nopco Chemical Co., Newark. New Jersey) 4.32% inertgelatin 0.18% sodium cellulose sulfate A low gel system operating inconjunction with a yellow diffusion transfer dye developer has beenprepared wherein the gelatin-to-dye ratio has been lowered from atypical value of 0.708 using Lomar D as an additive to 0.400 using SCS.This alteration represents a 43.0% reduction in the gelatin constituent.The formulation providing for this 0.400 gelatin/dye system was asfollows:

7.20% 1:1 chrome complexed azo methine dye developer 0.36% Lomar D(supra, utilized as a dispersing agent) 2.88% inert gelatin 0.17% sodiumcellulose sulfate A low gel'system operating in conjunction with a cyandye developer has been prepared wherein the gelatin-to-dye ratio hasbeen lowered from a typical value of 1.46 using Lomar D as an additiveto a value of 0500 using SCS. This alteration represents a 66.0%reduction in the gelatin constituent. The formulation providing for this0.500 gelatin/ dye system was as follows:

6.50% copper phtalocyanine dye developer 0.19% Lomar D (supra, utilizedas a dispersing agent) 3.25% inert gelatin 0.20% sodium cellulosesulfate An ultra-low gel system also is available in accordance with thepresent invention. The following formulations have, been developed toevolve a gel-dye (weight-to-weight) ratio of 0.300. For example, thefollowing formulation provided an ultra-low gel system for a magenta dyetransfer developer:

8.50% l:l chrome complexed azo dye developer 0.26% Lomar D (supra,utilized as a dispersing agent) 2.55% inert gelatin 0.08% sodiumcellulose sulfate An ultra-low gel system operating in conjunction witha yellow diffusion transfer dye developer has been prepared having thefollowing formulation:

8.50% l:l chrome complexed azo-methine dye developer 0.42% Lomar D(supra, utilized as a dispersing agent) 2.55% inert gelatin 0.08% sodiumcellulose sulfat An ultra-low gel system operating in conjunction with acyan dye developer has been prepared with the following formulation:

7.50% copper phtalocyanine dye developer 0.23% Lomar D (supra, utilizedas a dispersing agent) 2.25% inert gelatin 0.08% sodium cellulosesulfate In appropriate circumstances. the composite film unit structuremay be provided wherein the gelatino silver halide layers and dyetransfer developer-gelatin layers are provided as discrete layers ordepositions. With such an arrangement, select ones of the gelatinosilver halide layers may incorporate a salt of PVHP. while associateddye layers will contain the water-soluble cellulose salt as describedherein. Alternately. both the halide and the dye material dispersionsmay incorporate the water-soluble cellulose salt as a low gel systemadditive.

The additives described herein may be utilized in conjunction with anyof a broad variety of diffusion transfer film unit structures includingthe integral structure shown in the drawings as well as structuresdescribed in certain of the reference patents wherein theimage-receiving element is stripped from the photosensitive elementfollowing an appropriate interval of imbibition.

Since certain changes may be made in the above products and processeswithout departing from the scope of the invention herein involved, it isintended that all matter contained in the above description or shown inthe accompanying drawings shall be interpreted as illustrative and notin a limiting scnce.

We claim:

1. A photographic film unit, adapted to be exposed and processed toproduce a color diffusion transfer image. comprising:

a plurality of layers including at least one composite photosensitiveunit comprising a light-sensitive silver halide layer and, in contiguousplanar relationship thereto, a layer comprising a select associateddiffusion transfer dye image-forming material dispersed in a matrixcomprising gelatin and sodium cellulose sulphate;

receptor means including a layer adapted to receive diffusion transferdye-image forming material diffusing thereto as a function of thepoint-to-point degree of said photosensitive unit's exposure to incidentactinic radiation;

means incorporated with said film unit for selectively providingprocessing composition intermediate said receptor means and saidplurality of layers; and

means defining a dimentionally stable support for said plurality oflayers.

2. The photographic film unit of claim 1 wherein said sodium cellulosesulfate is present in an amount effective to provide for aweight-to-weight ratio, respectively, of said gelatin to said dyeimage-providing material of less than about 0.6.

3. The photographic film unit of claim 1 wherein said plurality oflayers comprise a first composite photosensitive unit including ablue-sensitive gelatino silver halide emulsion layer and a layercontaining a gelatin carried yellow dye image-forming material. a secondcomposite photosensitive unit including a green-sensitive gelatinosilver halide emulsion layer and a layer containing a gelatin carriedmagenta dye image-forming material; and a third cq posite photosensitiveunit including a red-sensitive gelatino silver halide emulsion layer anda layer containing a gelatin carried cyan dye image-forming material.

4. The photographic film unit of claim 3 wherein said gelatin within asaid dye-forming material containing layer is present in aweight-to-weight ratio with respect to said dye image-forming materialof less than about 0.6.

1. A PHOTOGRAPHIC FILM UNIT, ADAPTED TO BE EXPOSED AND PROCESSED TOPRODUCE A COLOR DIFFUSION RANSFER IMAGE, COMPRISING: A PLURALITY OFLAYERS INCLUDING AT LEAST ONE COMPOSITE PHOTOSENSITIVE UNIT COMPRISING ALIGHT-SENSITIVE SLIVER HALIDE LAYER AND, IN CONTIGUOUS PLANARRELATIONSHIP THERETO, A LAYER COMPRISING A SELECT ASSOCIATED DIFFUSIONTRANFER DYE IMAGE-FORMING MATERIAL DISPERSED IN A MATRIX COMPRISINGGELATIN AND SLDIUM CELLULOSE SULPHATE: RECEPTOR MEANS INCLUDING A LAYERADAPTED TO RECEIVE DIFFUSION TRANSFER DYE-IMAGE FORMING MATERIALDIFFUSING THERETO AS A FUNCTION OF THE POINT-TO-POINT DEGREE OF SAIDPHOTOSENSITIVE UNIT''S EXPOSURE TO INCIDENT ACTINIC RADIATION: MEANSINCORPORATED WITH SAID FILM UNIT FOR SELECTIVELY PROVIDING PROCESSINGCOMPOSITION INTERMEDIATE SAND RECEPTOR MEANS AND SAID PLURALITY OFLAYERS: AND MEANS DEFINING A DIMENTIONALLY STABLE SUPPORT FOR SAIDPLURALITY OF LAYERS.
 2. The photographic film unit of claim 1 whereinsaid sodium cellulose sulfate is present in an amount effective toprovide for a weight-to-weight ratio, respectively, of said gelatin tosaid dye image-providing material of less than about 0.6.
 3. Thephotographic film unit of claim 1 wherein said plurality of layerscomprise a first composite photosensitive unit including ablue-sensitive gelatino silver halide emulsion layer and a layercontaining a gelatin carried yellow dye image-forming material, a secondcomposite photosensitive unit including a green-sensitive gelatinosilver halide emulsion layer and a layer containing a gelatin carriedmagenta dye image-forming material; and a third composite photosensitiveunit including a red-sensitive gelatino silver halide emulsion layer anda layer containing a gelatin carried cyan dye image-forming material. 4.The photographic film unit of claim 3 wherein said gelatin within a saiddye-forming material containing layer is present in a weight-to-weightratio with respect to said dye image-forming material of less than about0.6.